Steam generator



June 22, 1943. G. A. REHM STEAM GENERATOR Filed June 18, 1941 5 Sheets-Sheet 1 0 w 2 4 2 2 2 U 2 a w: V 4 a 2 2 m g 6. o a W 4 L i I C, ,V/ h Nfi/ r T x J/ y n3 5. n m x M 3 M M w Fig.1

gvwma tbc Gus TA v-A. REHM June 22, 1943. GA. REHM STEAM GENERATOR Filed June 18, 1941 3 Sheets-Sheet 2 2 v2 42 4242 4/ 4v 42 Aw? 424v 4r v 3mm GUST/1 1/ A HEHM Patented June 22, 1943 Gustav A. Rehm, -Worcester, Mass, assignor to Riley Stoker Corporation, Worcester, Mass, a corporation .of Massachusetts Application June .18, 1941, Serial No. 398,651

2 Claims.

This invention relates. to steam generators, and more particularly to water tube steam generators adapted to be .fired with fluent fluids such as, for example, oil or gas.

There is a demand in the oil fields for an efficient steam generator of appreciable capacity which can be readily moved from place to place. Most Water tube steam generators as heretofore constructed require one or more walls of selfsupporting brickwork, and this fact renders them useless for service of this nature, since these walls are not only very heavy but they are also incapable of withstanding the jolts and -vibra tions incident to movement of the apparatus. A similar problem is presented in boilers for marine service, where the pitching and rolling of the ship render brick walls highlyundesirable.

It is accordingly one object of the invention to provide a water tube steam generator of appreciable capacity and so constructed and arranged that self-supporting brickwork will not be required.

It is a further object of the invention to provide a water tube steam generator which is particularly suited for use as a portable apparatus in the oil fields or as a marine boiler.

Itis a further object of the invention to provide a water tube steam generator which will operate efficiently at relatively high capacities and deliver steam comparatively free from moisture.

It is 'a further object of the invention to provide an efiicient water tube steam generator of appreciable capacity which can be completely assembled in the shop.

t is a further object of the invention to provide a water tube steam generator in which a rapid circulation of water will be maintained through all the steam generating tubes without the need for special water supply conduits.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a longitudinal section through a portable water tube steam generator, the section being taken on the line |-l of Fig. 2;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 33 of Fig. l;

Fig. 4 is a section on the line 4-4 of Fig. 1;

Fig. 5 is a side elevation showing one means for producing draft for operation of the apparatus; and

Fig. 6 is a view similar to Fig. 5 but showing a modification.

The embodiment illustrated comprises a longitudinal steam-and-water drum 10 mounted centrally in the upper portion of a rectangular setting I l, thelatter having two side walls I2, a rear wall M and a front wall I5. The drum l0 extends throughout the entire length of the setting. Two laterally spaced water drums or headers iii are mounted in the lower portion of the setting, these drums'being-parallel with the drum H] and of substantially the same length. In the rear portion of the setting the drums I6 are joined to the drum Ill thereabcve by means of upright water tubes 18 which form a convection tube bank. Although the lower drums l5 are comparatively small in diameter, they are spaced inwardly from the side walls I2 so that water tubes can be connected to each drum throughout the upper half of its circumferential surface. Thus a considerable number of the tubes l8 may be provided to ensure an adequate heating urface. In the particular embodiment illustrated there are fourteen of these tubes in each transverse row. The drums it are preferably spaced apart a distance approximately equal to one-half the width of the setting.

The front portion of the setting H encloses a combustion chamber 20 into which a suitable fluid fuel is introduced through a burner opening 24 in the front wall l5. The rear or inner face of this wall I5 is cooled and protected by a row of upright water tubes 22 which extend upwardly from the lower drums It to the upper drum lfl. Certain of these tubes 22 are bent laterally, as shown in Fig. 4, to avoid interference with the burner opening 2|. Except for this lateral-bending, the tubes 22 are preferably of the same shape as the convection water tubeslil.

The side walls [2 are likewise cooled and protected. For this purpose a row of water tubes 24 extends from .each water drum l6 upwardly along the inner surface of one side wall and thence to the upper drum I0. Preferably the lower portions of the two tube rows cross beneath the combustion chamber 20 and are covered with refractory material 25 to form a water cooled floor. The upper portions of these tube rows likewise cross above the combustion chamber and beneath the upper drum, their upper ends entering this drum from opposite sides and above the normal Water level.

It will now be apparent that each wall of the setting I I is cooled and supported against inward movement by a row of water tubes. The front wall it rests against the water tubes 22, and the rear wall Hi rests against the rearmost row of water tubes la. The front portions of the side walls l2 are supported 'by the water tubes 24, and the rear portions of these walls are supported by the outermost rows of water tubes Hi. In order to hold these several walls inwardly against the water tubes and at the same time minimize the infiltration of air, the entire setting is enclosed in a sheet metal casing 26. Each wall is preferably formed with an inner layer of refractory tile and an outer layer of a suitable heat insulating material, the weight and thickness being far less than would be required for a wall of self-supporting brickwork.

Referring now to Fig. 1, it will be seen that the gaseous products of combustion flow rearwardly from the combustion chamber into the convection tube bank l8, where these gases are deflected into a tortuous path by means of upright transverse baflles located among the rows of tubes. In the particular embodiment illustrated, there are four baffles and four gas passes, the rearmost or final pass leading upwardly to a gas outlet duct 3|. Preferably, the four rows of tubes in this final gas pass constitute an economizer to preheat the feed water. For this purpose the feed water is introduced through a nozzle 32 into the rear end of the drum I0, and a plate 33 extends across this drum immediately in front of the second row of tubes [8 (counting from the rear), the top of this plate extending somewhat above the normal water line. In addition, each of the lower drums I6 is provided internally with a transverse plate 35 in transverse alignment with the rearmost of the'bailies 30. Thus the feed water is forced to descend through the two rearmost rows of tubes l8 to the drums It, and then to ascend through the remaining tubes in the last gas pass before returning to the upper drum and mingling with the main body of boiler water therein. A steam outlet nozzle 3! is provided at the top of the drum ii], and a bafile plate 38 is mounted beneath the nozzle to prevent moisture particles from reaching the same. The usual water column 39 is mounted on the front end of the upper drum.

The steam generator as so far described is particularly suitable for use in the oil fields, and in this service it must occasionally be moved from place to place. In order to facilitate such movements, the entire structure is mounted on a frame or chassis 4! having four wheels 42 adapted' to rest upon the ground. The lower drums [6 may be welded to angles 43 (Figs. 2 and 3) extending longitudinally beneath the drums and bolted to the top of the frame. With this construction the steam generator can readily be drawn from one location to another by a tractor or other suitable apparatus. As shown in Fig. 5, an induced draft fan 45 and stack 46 may be mounted directly above the gas outlet duct 3| to form a permanent part of the steam generator. In the modified arrangement shown in Fig.

wardly among the convection water tubes It, with the baflles 30 deflecting these gases into a tortuous path before they reach the outlet duct 3|. The feed water will enter the drum l0 through the nozzle 32, and then flow through the tubes 18 in the fourth or rearmost gas pass before mingling with the main body of boiler water, so that these tubes will serve as an economizer to preheat the feed water and to reduce the gas temperature further than would otherwise be possible. The tubes [8 in the third gas pass will serve as downcomers to supply water from the drum ID to the two lower drums [6. The remaining tubes will all serve as steam generating tubes delivering steam directly to the upper drum. A very large part of the total steam will be generated in the side Water wall tubes 24, and since these tubes enter the upper drum high up on the sides thereof and above the normal water line there will be a minimum of commotion in the drum and very little tendency toward priming even at high loads.

The apparatus is particularly adapted for complete shop assembly, and for use as a portable 6, the gas outlet duct is connected by a breeching- 48 to an induced draft fan 48 mounted on a fixed stack 50. With this construction the breeching will be disconnected from the duct 3| before the steam generator is moved. To further facilitate the handling of the apparatus hanger loops 52 may be provided around the ends of the upper drum EU, as shown in Fig. 1, so that the entire steam generator may be suspended from an overhead crane when required for loading or unloading purposes.

The operation of the invention will now be apparent from the above disclosure. Fuel and air will be delivered through the opening 2| by a suitable burner, and combustion will take place in the chamber 20. The hot gases will flow rearunit or in marine service. No self-supporting brickwork is required, all the walls being supported by water tubes adjacent their inner surfaces and the steel casing 25 adjacent their outer surfaces. The water circulation is rapid and positive, and no special circulating tubes or headers are required. The structure is simple and compact, and so shaped as to minimize the cost of the casing. The tubes 24 shield the upper drum from the hot gases, and this drum can therefore be safely made with relatively thick walls suitable for high steam pressures.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A steam generator comprising a setting having two side walls, a front wall, and a rear wall, a steam-and-water drum located in the upper portion of the setting and extending substan tially the entire length thereof, two water drums located in the lower portion of the setting and extending substantially the entire length thereof, the water drums being spaced inwardly from the side walls, water tubes extending upwardly from the rear portions of the water drums to the upper drum to form a convection tube bank, and water wall tubes extending upwardly from the front portions of the water drums and along the side walls, the water Wall tubes crossing beneath the upper drum and entering the same from opposite sides above the normal water line.

2. A steam generator comprising a setting having two side walls, a front wall, and a rear wall, a steam-and-water drum located in the upper portion of the setting and extending substantially the entire length thereof, two Water drums located in the lower portion of the setting and extending substantially the entire length thereof, the water drums being spaced inwardly from the side walls, water tubes extending upwardly from the rear portions of the water drums to the upper drum to form a convection tube bank, and a row of water wall tubes extending laterally from the front portion of each water drum and above the other water drum, the water wall tubes then extending upwardly along the side walls, the two rows of water wall tubes then crossing beneath the upper drum and entering the same from opposite sides above the normal water line.

GUSTAV A. REHM. 

